Pavement



y 1943- F. w. SC HAEFFER 2,323,848

PAVEMENT Filed Feb. 13, 1941 Patented July 6, 1943 UNITED STATES PATENTFFlCE PAVEMENT Frederick William Schaefler, Chicago, Ill. ApplicationFebruary 13, 1941, Serial No. 378,697

3 Claims.

The present invention relates to pavements and particularly is directedtoward a novel constructlon of concrete pavements. The principal objectof the present invention is to provide concrete slabs of such acharacter that expansion thereof cannot cause the paving to buckle or"blow up." A further object is to provide a concrete pavement whereincracks are less likely to occur than in the pavements now in use.Another object is to provide a plurality of concrete slabs in a pavementin such a fashion that the cracks which must occur between the slabs dueto thermal expansion and contraction of the slabs will not affect to anydegree the riding characteristics of the roads surface.

With these and other objects in view I have provided a concrete pavementmade up of a D111- rality of sections or slabs. Two sizes and shapes ofslabs are used in my herein disclosed preferred embodiment. One slab,for convenience hereinafter called the large slab, may be, for example,forty feet long and twenty feet'wide. These .slabs are constructed withV-shaped or pointed ends,. the inclined sides thereof extending, forexample, to the apex from the quarter point of the slab. In a slab orthe given dimensions, therefore, the inclined sides are at an angle of45 with the centerline of the pavement.

The second slab, for convenience hereinafter called the small slab, ishalf as wide as the large slab and, for example may be aboutthree-fourths its length. Each end of the small slab is inclined tocooperate with and substantially abut a side of the V-shaped end of thelarge slab. Two

small slabs are placed side by side with their shorter sides in abuttingrelationship, whereby their inclined ends cooperate to define a V-shapednotch which receives a V-shaped end of a large slab. In this way, thelarge slabs are spaced by two side by side small slabs.

In a pavement construction of the character described, the thrust due toexpansion of the concrete slabs will not result in buckling or crackingof the slabs, but rather it will be dissipated in lateral movement ofthe small slabs. A reason for constructing these second slabs somewhatshorter than the large slabs is to insure that the small slabs readilycan be displacedin the case of a larger slab, friction between the slaband the subgrade might prevent this movement with the result that thepavement would buckle and crack.

Expansion does result in separating to an extent the small slabs.However, this longitudinal crack is in the center of the road or of thetwo lanes and is therefore relatively unobjectionable insofar as theriding characteristics of the road are concerned. It may be desirable toprovide a fabricated joint construction between the small slabs in orderto prevent moisture from entering the roadbed through the joint. It ispresent practice to provide a longitudinal joint of this character inconcrete pavements. In the pavement here contemplated. only aboutone-fifth as much of this longitudinal Joint construction is required asin the case of the conventional continuous centerline joint.

Inasmuch as the joints between the large and small slabs are inclined atan angle with respect to the centerline of the road, both front wheelsand both rear wheels of a car do not strike the joints at the same time.The result is easier and smoother riding and less impact damage to thepavement.

For a better understanding of the present invention, reference may behad to the accompanying drawing in which:

Fig. 1 is a plan view of a length of pavemen embodying the presentinvention;

Fig. 2 is a plan view of a length of pavement after expansion hasoccurred;

Fig. 3 is a sectional view on the line 3-3 of Fig. 2; and,

Fig. 4 i a plan view of a. four-lane pavement embodying my invention.

Referring now to the drawing, the pavement co prises a succession oflarge concrete slabs 5 spaced by pairs of side by side small slabs 6.The slabs 6 are one half as wide as slabs 5 and are somewhat shorter inlength. The slabs 5 are provided with pointed or V-shaped ends as shownat 1, which ends present sides 8. The intermediate small slabs 6 haveinclined ends 9 which are adapted substantially to abut the end sides 8of the large slab as shown by joints III. In the case of a two lanepavement, as illustrated in Figs. 1 and 2, joint ll between two side byside small slabs is on the centerline of the pavement.

Referring now to Fig. 2, the slabs have expanded so as to result in aslight lateral displacement of the slabs 6. Because of the size of slab5 and the friction between the slab and the subgrade, slab 5 is notdisplaced, and all the thrust due to expansion in both the slab 5 andthe slabs 6 is dissipated in the lateral movement of slabs 6.

Any conventional expansion joint may be used at the joints Ill. Thecharacter of the joint used depends, of course, on the amount ofexpansion expected as well as on the concrete used, the character of thesubgrade and the amount of trams: anticipated. In certain cases thejoints between the slabs may be filled with ordinary bituminous materialsuch as asphalt.

Fig. 4 shows my invention applied to a wider pavement, in this case afour-lane pavement. This embodiment includes slabs 5a and Ba which areimilar to slabs 5 and 6, respectively, described above. A slab I! placedin the center of the pavement has the configuration of two small slabsjoined along their long sides. Any desired joints may be used betweenadjacent slabs. Generally it is desirable to provide an expansion jointbet een the sides of adjacent slabs 50, as well as between the sides ofthe adjacent small slabs Ba and I5. It will be noted that the jointsbetween the sides of adjacent small slabs 6a and II are on a line whichbisects the angle defined by a V-shaped end of a slab is similar to theJoints between slabs 8 described above. Therefore, longitudinalexpansion of the large slabs (having V-shaped ends) results in lateraldisplacement of the small slabs 6a.

The concrete slabs may or may not be reeniorced, the matter ofreenforcement not being a question within the purview oi! the presentinvention.

From the above description, it will be seen that I have provided apavement construction wherein expansion of the composite slabs may notresult in a buckle or blow up. As the excessive strains which result inbuckles are not here present, cracks in the slabs are not as likely tooccur as in pavements subject to buckling. Also, the joints between theslabs are disposed at an angle with the line of trafilc whereby thevehicles may pass smoothly over the cracks to the greater comfort of thepassengers and to less impact on the pavement. Having thus described myinvention, what I claim as'new and desire to secure by Letters Patentis:

1. A pavement construction of the character described comprising slabsof paving material having V-shaped ends extending substantially from thequarter point'oi' said slabs, said slabs being spaced by a pair of sideby side shorter slabs which are half as wide as said first named slabs,each shorter slab having ends inclined in opposite directions wherebyadjacent ends cooperate to define a V-shaped opening which receives aV-shaped end of said first named slab.

2. A pavement construction of the character described including rows ofside by side slabs, said slabs having V-shaped ends, said rows beingspaced by side by side shorter slabs, said shorter slabs' havinginclined ends, the adjacent sides of which cooperate with andsubstantially abut the ends of said first named slabs, the Jointsbetween the longitudinal sides of adjacent shorter slabs being on a linewhich bisects the angle defined by a V-shaped end of a first named slab.

3. A pavement construotion of the character described comprising slabsof paving material having V-shaped ends extending substantially from thequarter point of said slabs, said slabs being spaced by a pair of sideby side shorter to define a V-shaped opening which receives a V-shapedend of said first named slab.

FREDERICK WILLIAM SCI-IAEFFER.

